Technical Field
The present disclosure relates to a lighting apparatus using an organic light emitting device with a simplified fabrication process, and a fabrication method thereof.
Description of the Related Art
In recent years, a fluorescent lamp or an incandescent lamp has been mainly used as a lighting apparatus. Among them, the incandescent lamp has a good color rendering index but has a low energy efficiency, and the fluorescent lamp has a good efficiency, but has a low color rendering index and contains mercury and thus has an environmental problem.
In order to solve such a problem of the lighting apparatus in the related art, in recent years, a light emitting diode (LED) has been proposed as a lighting apparatus. The light emitting diode is composed of an inorganic light emitting material, and has the highest luminous efficiency in a blue wavelength band, but has a lower luminous efficiency as it goes toward a red and a green wavelength band, which is a color having the highest visual sensitivity. Therefore, there is a problem in that the luminous efficiency is reduced when white light with a combination of a red light emitting diode, a green light emitting diode, and a blue light emitting diode is emitted. Furthermore, since the width of each emission peak is narrow when a red light emitting diode, a green light emitting diode, and a blue light emitting diode are used, there is also a problem in that the color rendering property deteriorates.
In order to solve such a problem(s), a lighting apparatus for combining a blue light emitting diode with a yellow colored phosphor instead of combining a red light emitting diode, a green light emitting diode and a blue light emitting diode to output white light has been proposed. The reason why the light emitting diode having such a structure is proposed is that a method of using only a blue light emitting diode having a higher luminous efficiency and using a fluorescent material that receives blue light to emit yellow light for the remaining colors is more efficient than that of using a green light emitting diode having a low luminous efficiency.
However, even in case of a lighting apparatus of combining a blue light emitting diode with a yellow colored phosphor to output white light, the fluorescent material itself that emits yellow light has a poor luminous efficiency, and thus there is a limit in enhancing the luminous efficiency of the lighting apparatus.